JP5432205B2 - Manufacturing method of woody synthetic building materials - Google Patents

Description

  Among the building materials used for window frames, decks, terraces, fences, handrails, pillars, louvers, benches, and other uses, in particular, a mixture of plywood wood powder and thermoplastic synthetic resin The present invention relates to a method for producing a woody synthetic building material that is molded from a material.

  Conventionally, natural materials such as wood have been the mainstream as building materials, but recently, woody synthetic building materials for building formed by mixing wood powder and thermoplastic synthetic resin have become known. It has come to be used as exterior building materials and interior building materials. Such wood-based synthetic building materials are notable because they can effectively use waste materials (waste materials such as natural timber and synthetic building materials), as well as save petroleum resources as raw materials and reduce manufacturing costs. Collecting.

JP 2006-192741 A JP 2006-305981 A Japanese Patent Laid-Open No. 2003-3660 JP 2002-187116 A JP-A-9-216500

  When resin molding is performed by mixing raw materials mixed with wood flour, it is known that moisture contained in wood flour becomes a problem. In addition, when using wood powder of synthetic building materials waste wood or plywood (wood fiber or a board produced by adding pressure to a piece of wood and pressing it) as wood powder, in addition to moisture In addition, an adhesive component is a problem.

  More specifically, if extrusion molding or injection molding is performed under general molding conditions using raw materials in which moisture or adhesive components remain, molding may become impossible due to abnormal foaming. There is a problem in appearance that a molded product as designed cannot be obtained due to distortion, the surface becomes rough, a variation in strength occurs, or a sufficient strength cannot be obtained. Therefore, in order to avoid these problems, it is preferable to thoroughly remove moisture and adhesive components from the raw material (powder or pellet) before molding.

  Therefore, in the conventional method for producing a woody synthetic building material using wood powder, after mixing wood powder and synthetic resin to produce raw material pellets, a drying process is carried out on those raw material pellets. It has been broken. By carrying out this drying step, moisture in the raw material pellets can be removed as much as possible.

  However, if the wood powder used contains an adhesive component, that is, if synthetic wood waste or plywood wood powder is used instead of natural wood wood powder, it will be dried against the raw material pellets. It is difficult to remove the adhesive component only by carrying out the process. For this reason, in the case of producing a wooden synthetic building material using synthetic building material waste and plywood wood powder, in order to suitably avoid the above-mentioned appearance, quality problems, or handling problems Decrease the mixing ratio of the wood flour (for example, 15% by weight or less of the synthetic resin raw material to be mixed) or leave the wood flour at a high temperature (for example, a temperature of 100 ° C. or more) for a sufficient time It has been considered that it is effective to perform raw material blending and pelletization after preliminarily evaporating moisture and adhesive components in the wood flour by heating over time.

  However, if the blending ratio of wood powder is reduced, there are problems in trying to effectively use the waste material, and it becomes difficult to express the wood texture in the molded product, which does not contribute to the saving of petroleum resources and the raw material cost. There is also a problem that it becomes bulky. Moreover, when heated for a long time at a high temperature (for example, a temperature of 150 ° C. or more) for the purpose of evaporating the adhesive component present in the wood flour, the wood flour itself changes (carbonization, etc.), discolors, decomposes, In addition to the problem that the basic state cannot be maintained, there is a problem that the time required for the process and energy consumption increase, and the manufacturing cost increases.

  The present invention has been made to solve the above-mentioned problems of the prior art, and can effectively use a waste material called plywood powder to save petroleum resources and keep raw material costs low. Another object of the present invention is to provide a method for producing a highly versatile woody synthetic building material, which can obtain a synthetic building material having a grain-like appearance similar to the texture of natural wood.

  The method for producing a woody synthetic building material according to the present invention comprises, as a main raw material, wood powder of a plywood produced by adding an adhesive to a wood fiber or a piece of wood, and applying pressure, and a thermoplastic synthetic resin. After the material added with the auxiliary material is heated and melted at 160 to 200 ° C., the material is pelletized to produce a raw material pellet. From the raw material pellet, the moisture content derived from the wood powder of the plywood and the contained adhesion Without positively removing the agent component, the raw material pellets are put into an extrusion molding machine or an injection molding machine and heated and melted at a temperature of 150 to 200 ° C. By causing a change in specific gravity, this is extruded from the mold or injected into the mold, and the residual moisture and adhesive components are used to reveal a wood-grain flow pattern on the surface of the molded product. The internal underlying flow patterns in complex structure of the molded product is characterized by the formation of (raw material different aspects entangled randomly).

  In addition, 100 parts by weight of thermoplastic synthetic resin and 30 to 100 parts by weight of plywood powder are blended as main raw materials, and 5 to 10 parts by weight of filler and 2-3 parts by weight of pigments are used as auxiliary raw materials. It is preferable to blend, and as the thermoplastic synthetic resin, it is preferable to use polyvinyl chloride powder, polystyrene powder, polyethylene powder, or polypropylene powder. Furthermore, as a thermoplastic synthetic resin, acrylic resin in one kind of material selected from polyvinyl chloride powder, polystyrene powder, polyethylene powder and polypropylene powder, or in combination of two or more kinds of materials It is preferable to use a material to which is added.

  According to the method for producing a woody synthetic building material of the present invention, it is possible not only to effectively use a waste material called wood powder of plywood, but also to obtain a synthetic building material exhibiting a grain-like appearance that approximates the texture of natural wood. . Moreover, since the blending ratio of the synthetic resin raw material can be reduced, petroleum resources as the raw material for the synthetic resin can be saved, and the raw material cost can be kept low by using the waste material.

FIG. 1 is a diagram schematically showing a part of a surface 4 and a cross section of a molded product manufactured by the method for manufacturing a wooden synthetic building material according to the present invention. FIG. 2 is a partially enlarged view of a cross section of the molded product shown in FIG. FIG. 3 is a diagram showing another configuration example of a molded product manufactured by the method for manufacturing a wooden synthetic building material according to the present invention. FIG. 4 is a partially enlarged view showing an example of the shape of the surface of a molded product manufactured by the method for manufacturing a wooden synthetic building material according to the present invention. FIG. 5 is an explanatory view of a method for producing the molded product shown in FIG. FIG. 6 is an explanatory diagram of a method for manufacturing the molded product shown in FIG. FIG. 7 is an explanatory diagram of a method for manufacturing the molded product shown in FIG. FIG. 8 is an explanatory diagram of a method for producing the molded product shown in FIG. FIG. 9 is a view showing another configuration example of a molded product manufactured by the method for manufacturing a wooden synthetic building material according to the present invention.

  Hereinafter, an embodiment of the “method for producing a wooden synthetic building material” of the present invention will be described. The method for producing a woody synthetic building material according to the present invention is basically to heat and melt a material obtained by adding an auxiliary material to a main material, pelletize it to produce a raw material pellet, and put this raw material pellet into an extruder. , Heating and melting and extruding from a mold to perform molding.

  In this embodiment, in addition to thermoplastic synthetic resin (polyvinyl chloride powder, polystyrene powder, polyethylene powder, polypropylene powder, acrylic resin, etc.) as a main raw material, plywood (wood fiber or wood piece adhesive) Plywood manufactured by adding and pressurizing, for example, MDF (Medium Density Fiber board), HDF (High Density Fiber board), particle board, etc.) wood flour is used. The blend of the main raw material is 30 to 100 parts by weight of plywood wood powder with respect to 100 parts by weight of the thermoplastic synthetic resin. Moreover, it is preferable to mix | blend 5-10 weight part of fillers and 2-3 weight part of pigments as an auxiliary material.

  Plywood wood powder, which is the main raw material, contains moisture and adhesive components (phenol resin, urea resin, etc.). Using the material containing this plywood wood powder, raw material pellets under general temperature conditions When water is produced, moisture and adhesive components remain in the interior. Then, when extrusion molding is performed under general molding conditions using raw material pellets in which moisture and adhesive components remain, as described above, abnormal foaming, distortion of the molded product, surface roughness, variation in strength However, in this embodiment, the raw material pellets are directly fed into an extrusion molding machine without actively removing the contained moisture and the contained adhesive component.

  At this time, by setting the molding conditions (heating and melting temperature, extrusion pressure, and residence time) within appropriate ranges, the above-mentioned problems can be suitably avoided, and residual moisture and adhesive components (Due to their changes), the material before being extruded from the die (die) (in the cylinder and the material in the cavity from the cylinder to the die) changes the specific gravity depending on the part, and the molded product The grain flow pattern can be displayed on the surface of the material, and a complex structure (a state in which different forms of raw materials are randomly entangled) can be formed inside the molded product. Thus, a synthetic building material having a grain-like appearance similar to the texture of natural wood can be obtained.

  The molding conditions are as follows. First, the heating and melting temperature of the raw material is set to 150 to 200 ° C. More specifically, among the cylinders of the extrusion molding machine, 120 to 150 ° C. for the hopper side portion, 140 to 190 ° C. for the intermediate portion, 170 to 190 ° C. for the die side portion, and about the die Is set to 160-200 ° C. Thereby, it adjusts so that the raw material in an extrusion molding machine may be heat-melted within the range of 150-200 degreeC. The extrusion pressure of the raw material is in the range of 10 to 20 MPa. The residence time of the raw material in the cylinder is 3 to 10 minutes on average.

  When raw material pellets containing moisture and adhesive components are put into an extruder and extrusion molding is performed under the above molding conditions, the raw material pellets are heated and melted in the cylinder, and moisture present in the raw materials And the adhesive component evaporates into gas (water vapor and other gases). At this time, the volume of these moisture and adhesive components expands dramatically (about 1700 times for water vapor), and the gas evaporated in the raw material hopper side region in the cylinder (gas separated from the raw material) Is discharged from the raw material hopper.

  And the raw material conveyed in the direction of die | dye in a cylinder will be in the state which foamed in the inside and surface vicinity by evaporation of a residual water | moisture content and a residual adhesive component. As a result, the specific gravity of the raw material in the cylinder varies depending on the part. More specifically, the portion having a relatively large amount of moisture or adhesive component has a low specific gravity (1.1 to 1.25 if the thermoplastic synthetic resin used as the main raw material is PVC, olefin, 0.95 to 1.15 in the case of a system, and the specific gravity of a portion having a relatively small residual amount is increased (1.25 to 1.4 for a PVC system, 1.15 to 1.25 for an olefin system). .

  In the cylinder, the raw material in which a part with a small specific gravity and a part with a large specific gravity are mixed is conveyed in the direction of the die without controlling the flow rate (for example, without attaching a filter or mesh), and the specific gravity is made uniform. As shown in FIG. 1, when the material is pushed into the die without being kneaded and extruded, a portion 2 having a small specific gravity and a portion 3 having a large specific gravity are randomly entangled (thickness of each portion: 1 to 1). About 5 mm) is formed. The part 2 having a small specific gravity has a relatively light color (a lot of foaming), whereas the part 3 having a high specific gravity has a relatively dark color (a little foaming), and the shade of the color tone is the surface of the molded product. In 4, a flow pattern is formed.

  In addition, when the raw material passes through the die and contacts the finished surface of the die and the cooling sizer and is cooled, as shown in FIG. 2, the portion 2 having a small specific gravity has a rough surface because there are many foamed portions, A surface having a slight unevenness (uneven surface 2a) is formed. On the other hand, the portion 3 having a large specific gravity is not rough because the foamed portion is small, and a smooth surface (smooth surface 3a) like a mirror surface is formed along the finished surface of the die. The difference in texture between the uneven surface 2a and the smooth surface 3a and the difference in light reflection form a flow pattern on the surface of the molded product.

  As described above, according to the method according to the present embodiment, due to the difference in specific gravity generated in the raw material, the shade of color tone, the difference in texture, and the difference in the light reflection state occur, and by combining them, molding is performed. A flow pattern is formed on the surface of the object, and it is possible to manufacture a woody synthetic building material having a wood texture similar to the texture of natural wood.

  In addition, if the molding conditions are outside the above-described appropriate range, the following problems may occur. First, if the heating and melting temperature of the raw material is lower than 150 ° C., there is a problem that the adhesive component contained in the raw material pellet does not sufficiently decompose and foam, and if it is higher than 200 ° C., it is included in the raw material pellet. There is a problem that the decomposition of the wood flour that has started, and the performance cannot be maintained. Also, if the extrusion pressure of the raw material is less than 10 MPa, there is a problem that the raw material cannot be extruded from the die. If it is larger than 25 MPa, the discharge speed of the molded product from the die becomes too fast, and cooling control (cooling sizer) , And cooling control in the water tank) become difficult, and there is a problem in terms of durability of the die. Furthermore, if the residence time of the raw material is shorter than 3 minutes, the fusion of the raw material pellets and the fusion of the layers formed by melting the raw material pellets (layers having relatively low specific gravity and relatively large portions) are not possible. There is a problem that it is sufficient, and if it is longer than 10 minutes, there is a problem that abnormal foaming or decomposition of the raw material occurs.

  As described above, in the conventional method for producing a woody synthetic building material, the moisture and adhesive components remaining in the raw material pellets cause deterioration in the appearance and quality of the molded product. Although it was thought that it should be excluded from the pellets, in the present embodiment, conversely, by utilizing those moisture and adhesive components present in the raw material, that is, the molding conditions are appropriately set. By setting the range, the aspect in which they (water and volatile substances in the adhesive component) are separated from the raw material at the time of molding (the process from the cylinder to the die) is controlled. It is possible to obtain a wood-grained synthetic building material that approximates the texture of

  Therefore, unlike the case of the conventional method for producing a woody synthetic building material, when generating raw material pellets, the moisture and adhesive components contained in the wood powder of plywood used as the main raw material are It is necessary to control so that a predetermined amount or more remains inside the raw material pellets. Therefore, in this embodiment, a raw material (a material obtained by adding an auxiliary raw material to a main raw material) is heated and melted under a temperature condition of 160 to 200 ° C., and then cooled and pelletized. When raw material pellets are produced under such temperature conditions, when 100 to 100 parts by weight of thermoplastic synthetic resin is blended with 30 to 100 parts by weight of plywood wood, about 0.3 to 0.9% by weight for moisture, As for the volatile substances (toluene, xylene, etc.) contained in the adhesive component, those having a residual amount of about 0.5 to 1% by weight are obtained.

  Then, when raw material pellets containing moisture and an adhesive component in the above range are put into an extrusion molding machine and extrusion molding is performed under the appropriate molding conditions as described above, the grain that approximates the texture of natural wood A synthetic building material that exhibits a toned appearance can be obtained.

  In this embodiment, the raw material pellets are put into an extrusion molding machine and the woody synthetic building material is manufactured by extrusion molding. However, the raw material pellets can be put into an injection molding machine and manufactured by injection molding.

  Further, when forming, the die has a large number of ridges and dents formed on the surface, and after performing the grinding step described later, the ridges 5 and the dents as shown in FIG. 6, the top portion 7, the deepest portion 8, the gently inclined portion 9, and the steeply inclined portion 10 are formed, and the distance between the top portions 7 of the two adjacent protruding ridges 5, the width of the top portion 7 of the protruding ridge 5, A die designed so that the depth of the deepest portion 8 of the concave stripe 6, the angles of the gently inclined portion 9 and the steeply inclined portion 10, the curvature of the curved surface of the concave stripe 6, etc. are irregularly arranged in the lateral width direction. It can also be used.

  In addition, it is known that when the raw material resin or the like is cooled to a normal temperature state after molding, a deformation called “sink” (deformation due to shrinkage accompanying cooling of the raw material resin) occurs in the molded product. FIG. 4 is a partially enlarged view showing an example of the shape of the surface of the molded product after molding. In this figure, the broken line indicates the outline of the die 12. As shown, the shape of the surface of the cooled molding does not necessarily match the contour of the die 12 as a result of “sinks”.

  Therefore, after cooling the molded product, of the many ridges 5 and the ridges 6 formed on the surface, the tip portions of the ridges 5 are removed along a certain reference line L (see FIG. 5). The process to perform (the grinding process of the ridge tip part) is carried out. In addition, the removal of the front-end | tip part of the protruding item | line 5 is carried out using grinding machines (or cutting devices), such as a sander, a grinder, an electric plane apparatus, or a wire brush roll, (reference line of FIG. 5). (A portion above L) is ground (or cut). By carrying out this process, even if shrinkage deformation due to “sinks” occurs on the surface, and even if the mode and degree of shrinkage deformation vary depending on the part, the surface has a flat surface without distortion as a whole. A synthetic wood building material can be manufactured.

  When molding is performed by extruding a synthetic resin mixed with wood powder from a die, a layer (surface layer 11a) in which the distribution density of the wood powder is relatively low and the distribution density of the synthetic resin is high in the vicinity of the surface (FIG. 6). Reference) is formed. On the other hand, a layer (inner layer 11b) in which the synthetic resin and the wood flour are evenly mixed is formed inside the molded product (portion other than the vicinity of the surface).

  When the tip portion of the ridge 5 (the portion above the reference line L shown in FIG. 6) is cut and removed, the inner layer 11b is exposed at the top portion 7 of the ridge 5, as shown in FIG. The surface layer 11a remains in the other portions (the concave strip 6, the gently inclined portion 9, and the steeply inclined portion 10).

  Since the surface layer 11a has a high distribution density of synthetic resin as described above (a low distribution density of wood flour), a smooth surface is easily formed along the finished surface of the die compared to the inner layer 11b. Since the small portion 2 has many foamed portions, in the portion of the surface layer 11a where the portion 2 having a small specific gravity is exposed, the skin 2 is eventually roughened, and an uneven surface 2a (see FIG. 2) having slight unevenness is formed. It will be. In the portion where the portion 2 having a small specific gravity is exposed, the light reflectance is low. On the other hand, in the portion of the surface layer 11a where the portion 3 having a large specific gravity is exposed, the surface is not rough because there are few foamed portions, and a smooth surface 3a (see FIG. 2) is formed along the finished surface of the die, The light reflectivity increases.

  Therefore, in the concave strip 6, the gently inclined portion 9, and the steeply inclined portion 10 where the surface layer 11a remains, the portion where the portion 3 having a large specific gravity is exposed is glossy, and the appearance changes in color tone depending on the viewing angle. It becomes. In particular, since the vicinity of the deepest portion 8 of the concave stripe 6 is configured as a concave curved surface, when the portion 3 having a large specific gravity is exposed in the vicinity, light from multiple directions is reflected and various color tones are reflected. It becomes.

  On the other hand, since the inner layer 11b has a higher wood powder distribution density than the surface layer 11a, when the inner layer 11b is exposed outward, a large amount of wood powder mixed with the synthetic resin appears on the surface. It will be. And since the surface of these wood powders is not smooth, the reflectance of light is low. Therefore, the top part 7 of the ridge 5 where the inner layer 11b is exposed is a luster in which the color of wood powder and the color of synthetic resin are mixed. The color tone does not change so much even if the line-of-sight angle changes.

  Therefore, the surface has a different color tone, that is, a glossy color tone that changes variously depending on the line of sight angle (concave strip 6, gently sloping portion 9 and steeply sloping portion 10), and a glossy mixture of wood flour color. In addition to the color tone (the top 7 of the ridge 5) appearing in contrast, the portion 2 having a low specific gravity is a relatively light color, whereas the portion 3 having a high specific gravity is a relatively dark color, Since a difference in texture and a difference in light reflection occur, the top 7 of the ridge 5 where the inner layer 11b is exposed also has the ridge 6 where the surface layer 11a remains, the gently inclined portion 9, and the steep Even in the inclined portion 10, a flow pattern is formed by the shade of the color tone, the difference in texture, and the difference in light reflection. As a result, the surface of the wood composite building material is a flat surface with a natural wood texture that exhibits a grain-like appearance that approximates the texture of natural wood due to uneven color tone, uneven light reflection, and flow pattern. can do.

  Moreover, in this wooden synthetic building material, between the two ridges 5 or between the two ridges 6, a gently inclined portion 9 having a relatively gentle angle, and a steeply inclined portion 10 having a tighter angle than those, In the case where two types of inclined portions are arranged in combination one by one, and the ridges 5 and the ridges 6 are configured so that the left and right are asymmetrical with respect to the center of the top portion 7 or the deepest portion 8. Compared with conventional woody synthetic building materials, it is possible to form a surface having a texture that is closer to that of natural wood, with a more uneven color tone and appearance due to uneven light reflection due to the shape.

  More specifically, the natural wood board has a grain composed of a hard and dark colored part and a soft and pale colored part, so that the surface becomes smooth when sawing. Even when processed, when a long time elapses in a state exposed to wind and rain or sunlight, irregularities are generated on the surface along the grain part (boundary part of the annual ring). The uneven shape on the surface is formed by thinning and denting the portion between the grain and the grain, and the point of the grain being relatively convex. And while the slope on one side of the ridges of the grain is a relatively gentle angle, the slope on the opposite side is often a steep angle. This tendency appears more markedly in the grain material than in the mesh material.

  Between the two ridges 5 or between the two ridges 6, there are two types of inclined parts, a gentle inclined part 9 having a relatively gentle angle, a steeply inclined part 10 having a tighter angle than those, and a two-type inclined part. When arranged in combination one by one, it is possible to make a shape simulating the shape of the secular change that appears in the natural wood as described above. Therefore, it is possible to produce a woody synthetic building material having a texture closer to that of natural wood than a conventional woody synthetic building material.

  Also, the distance between the tops 7 of the two adjacent ridges 5, the width of the top 7 of the ridges 5, the depth of the deepest part 8 of the ridges 6, the inclination angle of the gently inclined part 9, the steeply inclined part When the inclination angle of 10 and the curvature of the curved surface constituting the concave stripe 6 are not constant, a plurality of variations are set for each factor, and they are arranged irregularly, the surface is varied. Even if only one type of resin raw material (one type of material that is a mixture of thermoplastic synthetic resin, wood flour, and auxiliary materials) is used, A plane with a natural wood texture can be constructed.

  Moreover, after forming the top part 7 as shown in FIG. 7 by carrying out the grinding process of the ridge tip part, further using a grinding device having flexibility in the grinding part, such as a wire brush roll. When the step of grinding the shoulders 13 and 13 of the top 7 of the ridge 5 so as to be in the state shown in FIG. 8 (grinding step of the ridge shoulder) is performed, the surface layer 11a is cut to some extent. As a result, an appearance having intermediate characteristics between the surface layer 11a and the inner layer 11b is obtained. More specifically, the layer appearing by scraping the shoulder portions 13 and 13 shown in FIG. 8 with a wire brush roll or the like has a wood powder distribution density lower than that of the inner layer 11b and higher than the surface side of the surface layer 11a. Get higher. Accordingly, the degree of gloss is also intermediate between the surface side of the surface layer 11a and the inner layer 11b, and thus an appearance in which more various color tones are combined in a complex manner is exhibited, and the surface has a texture closer to that of natural wood. The provided plane can be configured.

  In addition, after performing the grinding process of the protruding item | line front-end | tip part, the grinding process of a protruding item | line shoulder part is not performed, but removal of the front-end | tip part of the protruding item | line 5 and the protruding item | line 5 are performed using grinding devices, such as a wire brush roll. The both shoulder portions 7a and 7a may be simultaneously cut in one step.

  Moreover, as shown in FIG. 9, the basic shape between the ridges 5 and the ridges 6 extending in the longitudinal direction on the surface is formed using a die that is formed as a curved surface instead of an inclined surface. It can also be done. In this case, a plurality of variations are set for the curvatures of the curved surfaces, and they are arranged irregularly. Further, the ridges 5 (all the ridges 5 formed on one surface are formed. It is preferable that 30% or more (more preferably 50% or more) of the left and right shapes are asymmetrical with respect to the center of the top portion 7.

  Even when configured in this way, it has a characteristic that it is glossy, and the color tone that varies variously depending on the viewing angle and the lusterless color tone that mixes the color of the wood powder appear, and has a wood texture A surface can be formed. Further, as the curved surface from the top 7 of the ridge 5 to the deepest portion 8 of the concave 6, curved surfaces having different curvatures are irregularly arranged, and the ridge 5 and the concave 6 are the center of the top 7 or the deepest portion. When configured to be asymmetrical with respect to 8 as a reference, a surface having a texture closer to that of natural wood is formed as compared with a conventional woody synthetic building material.

  Further, the distance between the tops 7 of the two adjacent ridges 5, the width of the top 7 of the ridges 5, the depth of the deepest part 8 of the recesses 6, etc. are not constant, and there are a plurality of factors for each factor. When variations are set and they are arranged irregularly, the surface will have an appearance that is a complex combination of various colors, and one kind of resin raw material (thermoplastic synthetic resin and wood flour) Even if only one kind of material mixed with the auxiliary material is used, a plane having a natural wood texture can be formed.

  In FIGS. 1 to 9, for the sake of convenience, the portion 2 having a small specific gravity and the portion 3 having a large specific gravity are clearly divided and schematically represented. It does not exist, and a stepwise change mode (gradation) is exhibited with respect to the difference in specific gravity value and color density.

2: Site with a low specific gravity,
2a: uneven surface,
3: Site with large specific gravity,
3a: smooth surface 4: surface,
5: ridges,
6: Concave,
7: Top,
8: deepest part,
9: Slightly inclined part,
10: Steeply inclined part,
11a: surface layer,
11b: inner layer,
12: Die,
13: Shoulder

Claims (4)

A method for producing a woody synthetic building material mainly composed of wood powder of plywood produced by adding an adhesive to a wood fiber or a piece of wood, and applying pressure, and a thermoplastic synthetic resin,
A material obtained by adding a secondary raw material to a main raw material in which 100 parts by weight of a thermoplastic synthetic resin and 30 to 100 parts by weight of plywood are blended is heated and melted at a temperature of 160 to 200 ° C., and then pelletized . Producing raw material pellets in which moisture is 0.3-0.9% by weight and volatile substances contained in the adhesive component remain 0.5-1% by weight ,
The raw material pellets are put into an extrusion molding machine or an injection molding machine without actively removing the moisture content and the contained adhesive component derived from the wood powder of the plywood from the raw material pellets, and 150 to 200 ° C. The raw material that is heated and melted within the range of the above and is conveyed in the cylinder of the extrusion molding machine or injection molding machine is foamed in the vicinity of the inside and near the surface by evaporation of residual moisture and residual adhesive components. A method for producing a woody synthetic building material, characterized in that a specific gravity change and a flow change are created by extruding a mold from a mold or injected into a mold to form a pattern on the surface and inside of the molded product. 120-150 ° C. for the hopper side part, 140-190 ° C. for the intermediate part, 170-190 ° C. for the die part, and 160-200 ° C. for the die. The method for producing a woody synthetic building material according to claim 1, wherein the material is heated and melted and extruded from a mold . The method for producing a woody synthetic building material according to claim 2, wherein the residence time of the raw material in the cylinder is 3 to 10 minutes . In the cylinder, the raw material in which a part with a low specific gravity and a part with a high specific gravity are mixed due to evaporation of residual moisture and residual adhesive components is conveyed in the direction of the die without controlling the flow rate, and the specific gravity is made uniform. pushing the die without kneading for by extruding a large portion of the small region and the specific gravity of specific gravity and forming a multi-layered structure entangled randomly in the molded article, according to claim 2 or claim 3 A method for producing a woody synthetic building material according to 1.

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